Complications of gastric bypass surgery include leakage from the gastrojejunal anastomosis with abscess formation and anastomotic stenosis. Using interventional radiologic techniques, we have treated 18 patients with such complications following surgery for morbid obesity, with clinical success in 11. Procedures included 9 abdominal abscess drainages and 7 balloon dilatations of stenotic or occluded gastrojejunal anastomoses. Eight of 9 abscesses resolved completely; 3 of 7 balloon dilatations resulted in long-term clinical improvement. We describe the techniques used as well as problems encountered in these patients.